/*
 *  Copyright (c) 2011 Mathew Hall.
 *  All rights reserved.
 * 
 *  Redistribution and use in source and binary forms, with or
 *  without modification, are permitted provided that the following conditions
 *  are met:
 * 
 *  Redistributions of source code must retain the above copyright
 *  notice, this list of conditions and the following disclaimer.
 *  Redistributions in binary form must reproduce the above
 *  copyright notice, this list of conditions and the following
 *  disclaimer in the documentation and/or other materials provided
 *  with the distribution.
 *  Neither the name of the University of Sheffield nor the names of its
 *  contributors may be used to endorse or promote products derived
 *  from this software without specific prior written permission.
 * 
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *  CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 *  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 *  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 *  EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package search.fitnessfunctions

import primitives.cluster.*;
import search.fitnessfunctions.util.EdgeSubsumptionTransformer


/**
 *
 * @author Mathew Hall
 */
class CyclomaticComplexityFitnessFunction extends TreeFitnessFunction{
    
    double evaluate(ClusterHead tree){
        
        ClusterHead flat = EdgeSubsumptionTransformer.transform(tree);
        
        return complexity(flat)
        
        
        
    }
    
    static double complexity(ClusterHead tree){
        int e = tree.nodes.collect{
            it.transitionsAsT.size()
        }.sum(0)
        
        int n = tree.nodes.size()
        
        return 1d/Math.max(e - n + 2,0 + Double.MIN_VALUE);
        
        
    }

	Boolean subsumes() {
		return true;
	}
	
	
}

